Photographic recording materials, for example microfilm or roll film, consist of a transparent support, for example of cellulose triacetate, and a plurality of layers applied to one side of the support. The layers consist essentially of gelatine in which the photographically important constituents, such as silver halide crystals, color couplers and other substances, are embedded.
These materials have a tendency when dry to curl in such a way that the emulsion side, i.e. that side of the support to which the photographically important gelatine layers are applied, lies on the inside (E.sub.i state). This tendency to curl is intentional and is brought about in the production of the material by the tractive force which the gelatine exerts during drying. To ensure that this tendency to curl does not become excessive, so-called NC (non-curling) layers are applied to the back of the support, counteracting the tendency to curl and ensuring that the film lies sufficiently flat in the camera or printer (copier) to avoid blurring during exposure and copying.
The NC layers typically consist of gelatine. It has now been found that, in the processing of materials of the type in question, the NC layers, which have a thinner coating of gelatine than the front layers, dry more quickly than the front layers and, as a result, exert a tractive force which causes the film to curl in such a way that the photographically important gelatine layers (=emulsion side) curl outwards in the meantime (E.sub.a state), so that emulsion layers can easily be damaged, particularly in the drying section of compact laboratories, so-called "minilabs", unless the film is guided over a relatively long distance (about 50 cm) between pairs of rollers during drying. In the extreme case, the end of the film, which is not additionally guided, can enter the paired transport rollers at the dryer exit obliquely and still with a pronounced curve so that the film can develop kinks.
Compact laboratories are normally laid out in such a way that the beginning of a film to be processed is attached to a perforated carrier tape and is transported through the laboratory with that tape. The end of the film is freely movable. The film is generally dried with air heated to around 50.degree. C.